mineral

Turquoise

CuAl6(PO4)4(OH)8·4H2O

Hardness: 5 to 6 on Mohs scale. Color: Robin's-egg blue to sky blue, blue-green, and apple green. Luster: Waxy to subvitreous or dull. Crystal Structure: Triclinic (rarely forms distinct crystals, usually microcrystalline or massive). Specific Gravity: 2.6 - 2.9.

Hardness: 5 to 6 on Mohs scale
Color: Robin's-egg blue to sky blue, blue-green, and apple green
Luster: Waxy to subvitreous or dull

Identified July 27, 2026More mineral →

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Physical properties

Formation & geological history

Formed by secondary or supergene enrichment processes when acidic, copper-rich circulating groundwater reacts with aluminum and phosphorus-bearing minerals in arid regions.

Uses & applications

Highly valued as an ornamental gemstone, used extensively in Native American and Middle Eastern jewelry, carvings, beads, and decorative lapidary arts.

Geological facts

Turquoise is one of the oldest known gemstones, mined since at least 6000 BCE in the Sinai Peninsula. The name comes from the French 'turquois', meaning 'Turkish', as it was originally brought to Europe via trade routes through Turkey.

Field identification & locations

Identified by its distinctive turquoise-blue color, opaque body, waxy luster, and often dark brown or black matrix veining. Major sources include the Southwestern United States (Arizona, Nevada), Iran (Persia), China, and Egypt.